注水开采油藏注采平衡系统研究

油藏进行注水开发后，建立合理的注采平衡系统，不仅可以充分发挥油水井的生产能力，节约能耗，同时为获得最大产液量创造条件。为了搞清在高含水采油阶段，油藏产液能力，吸水能力，含水上升等变化规律，可以结构合方面因素，如地层压力，流压，注水压力，采液（油）指数及油水井数的变化等，从油藏实际出发，在分析研究的基础上，利用注采平衡交汇图，进行注采平衡系统研究。     

特高含水油田水驱注采结构优化方法研究

针对喇嘛甸油田喇北北块进入特高含水期开发后,水驱低效、无效循环日益突出的矛盾,为了更好优化产液、注水结构,把注水、产液结构由层系间优化转变为层系内不同含水井、不同含水层之间的优化,将水驱油井按含水、沉没度进行分级,对不同含水级别的井,采用不同的原则和方法进行提液和控液,使水驱油水井在注采平衡的基础上,减少无效、低效注采循环。通过注、采结构的精细优化调整,油田水驱自然递减率、含水上升率得到有效控制。     

水驱油田合理注采规模的影响因素

合理注采比是表征油田注水开发过程中注采平衡状况的一项重要指标,反映了产液量、注入量与地层压力之间存在的关系,为研究合理注采规模提供重要依据。在高含水期油藏注水开发过程中,合理注采规模研究对提高油田开发水平和管理水平具有重要意义。在保证产量的前提下,为了地层压力保持水平、控制含水上升速度,以当前产量规模进行预测,对注采状况进行评价,以定产配注为原则,基于利用物质平衡方程确定的合理注采比,对注入量进行调整,从而确定合理的注采规模。     

油井注采压力系统适应性评价

合理的地层压力水平不仅可以使油井取得较高的采收率,而且能够降低注水开发的难度。通过静水柱压力法、低渗透油藏确定法、原油粘度确定法和物质平衡等方法,确定合理地层压力保持程度。注水井合理井底流动压力的确定是合理注水压力系统界限研究的重要内容之一,同时也是油藏注水开发设计的重要依据,在确定合理地层压力保持程度的基础上确定合理流压与合理注水压力。通过目前生产现状对比,评价目前注采压力系统,从而确保较高的采收率,降低注水开发的难度。     

尕斯库勒N1-N21油藏开发存在的问题及稳产潜力浅析

尕斯库勒N1-N21油藏,地质储量4604万吨,可采储量1474.28万吨。目前有采油井399口、注水井164口,年产油56.38万吨,累计产油1012.77万吨;年注水108.15万方,累计注水775.47万方;综合含水66.01%,采出程度22%。目前,该区域面临产量递减快、油水连通率低、含水上升较快、局部供液不足等问题,如何提高油藏的采油速度和采出程度,保持油藏的稳产,是今后工作的重点方向。     

张巨河张19-1断块注水开发保持合理地层压力的优选

在注采保持平衡的基础上,对注水开发单元不同含水、不同压力保持水平下的合理最小井底流压和合理最大注水压力等参数进行研究,绘制出不同井网下的注采系统平衡图,在此基础上进行压力保持水平优选,确定出压力保持水平界限,用来指导今后注水开发。     

元城油田元54区稳产技术对策研究

主要以元城油田元54区长1油藏为研究对象,对长1低渗透油藏的水驱状况、驱替压力系统、产量递减规律、含水上升规律、采液采油指数变化规律等开发特征进行研究,总结了油藏稳产面临的主要问题,以"挖掘剩余油,提高单井产能与采收率"为目的,提出了精细注水调控、水井调剖治理、油井解堵、合理优化技术参数等一系列的稳产技术对策。     

K油田低成本开发策略研究与应用

在国际油价持续走低的大环境下,无效或低效措施投入,已经严重影响油田开发的经济效益。本文根据投入产出均衡理论,基于K油田油水井措施现状,以经济极限增油量作为评价标准,筛选并制定出低成本的强化采液增产策略。通过无因次采液(油)指数、注水波及体积系数、驱油效率、地层压力和注水利用率等强化采液的可行性分析,在11个注采井组优化强化采液设计,集中实施取得较好的增油效果,赢得更高的经济收益。     

长庆油田M油藏注水系统分析

M油藏属于低渗透裂缝性油藏,本文讨论了M油藏注水系统的特点,分析了该油藏在注水过程中采液、采油强度变化规律、即时含水注采比的、存水率的变化特征、以及水驱指数的特征评价,指出了该油藏注水系统中主要存在的问题：①强化注水没有达到提高区块压力的目的;②区块无效注水太多。建议采取以下措施：①加强油藏监测工作,弄清注入水的去向,为以后的注水提供参考;②进一步完善注采系统,提高水驱波及体积,实现均衡开采。     

北16井区改善注水开发效果研究

针对北16井区构造复杂,储层非均质性强的特点。在油藏注水开发中,部分水井欠注,注采压差大,渗流阻力大等问题。采取了高压注水,分注,调剖等措施,以调整注采结构,完善注采系统。该措施实施后有效控制了含水上升速度,提高了注水波及系数,使得该区块注水开发效果得到改善。     

Simulation and experimental studies on fluidization properties in a pressurized jetting fluidized bed

The influence of pressure on the bubble size and average bed voidage has been investigated experimentally and computationally in a circular three-dimensional cold-flow model of pressurized jetting fluidized bed of 0.2 m i.d. and 0.6 m in height with a central jet and a conical distributor, which roughly stands for the ash-agglomerating fluidized bed coal gasifier. The pressurized average bed voidage and bubble size in the jetting fluidized bed were investigated by using electrical capacitance tomography (ECT) technique. The time-averaged cross-sectional solids concentration distribution in the fluidized bed was recorded. The influence of pressure on the size of bubble and the average bed voidage in a pressurized fluidized bed was studied. Both experimental and theoretical results clearly indicate that there is, at the lower pressure, a small initial increase in bubble size decided by voidage and then a decrease with a further increase in pressure, which proves the conclusion of Cai et.al. [P. Cai, M. Schiavetti, G. De Michele, G.C. Grazzini, M. Miccio, Quantitative estimation of bubble size in PFBC, Powder Technology 80 (1994) 99-109]. At higher pressure, bubbles become smaller and smaller because of splitting. The average bed voidage increases gradually with the pressure at the same gas velocity. However, there is a disagreement between the experimental results and simulation results in the average bed voidage at the higher gas velocity, especially at the higher pressure. It suggests that the increase in density of gas with pressure may result in the drag increase and the drag model needs to be improved and revised at higher pressure.     

Voidage waves in hydraulic conveying through narrow pipes

The nature of voidage waves in hydraulic conveying systems has been investigated computationally in this study. Voidage waves consisting of alternating regions of high and low solid fractions were observed to form spontaneously in hydraulic conveying through vertical pipes. The wavelengths of these voidage waves were found to be inversely related to mean solid fraction but independent of liquid conveying velocities for elastic solid particles. The wave structure in terms of the thickness and shape of the solid fraction profile over each dense phase was dependent on the mean solid fraction used. Pressure distributions along the longitudinal direction of the conveying pipe exhibited an interesting ‘step’ profile due to unequal pressure drops across the dense and dilute regions. With inelastic solid particles, a lower tendency for voidage wave formation was observed and a phase diagram was constructed to show combinations of operating conditions under which voidage waves would form. Finally, the study of voidage waves in hydraulic conveying systems was extended to the case of hydraulic conveying through horizontal channels. In addition to the various system parameters, voidage wave formation in this case was also affected by gravitational settling of the solid particles.     

CFD modeling of pressure drop and drag coefficient in fixed and expanded beds

The aim of this study is computational fluid dynamic (CFD) simulation of the single-phase pressure drop in fixed and expanded beds. A fixed bed with a column to particle diameter ratio (D/d_p) of 5 and having 151 particles arranged in 8 layers was taken as a computational geometrical model. In the case of expanded beds, 0.605 voidage bed consisted of 105 particles and 0.783 voidage bed consisted of 55 particles. Simulations were performed in the creeping, transition and turbulent flow regimes, where Reynolds number (d_pV_Lρ_L/μ_L) was varied from 0.1 to 10,000. The deviations from Ergun's equation due to the wall effects, which are important in D/d_p < 10 beds, were well explained by the CFD simulations. Thus, an increase in the pressure drop was observed due to the wall friction in the creeping flow, whereas, in turbulent regime a decrease in the pressure drop was observed due to the channeling near the wall. Energy balance has been established through the CFD predicted values of energy dissipation rates (viscous as well as turbulent).     

喷动流化床流动特性数值模拟

为了捕捉喷动流化床中微观层次上的颗粒运动信息,建立了基于CFD的二维非稳态喷动流化床欧拉-欧拉两相流模型。分析了不同流化气速对喷动流化床气固流动特性的影响,即不同工况下的炉内压力降、颗粒浓度、床内空隙率分布、气体速度分布和固体颗粒速度分布。数值模拟研究结果表明:随流化气速的增大,压降和炉内平均空隙率逐渐增大,密相床层高度逐渐增加,沿着轴向方向的气体流量增大,喷动气的射流深度逐渐增加,同时射流半径也逐渐增加。     

Spout voidage distribution,stability and particle circulation rates in spouted beds of coarse particles—I. Theory

Mass and momentum balance equations are used with a derived expression for the interaction force between the fluid and particle phases to calculate the axial spout voidage distribution and particle circulation rate in a spouted bed of coarse particles. The voidage profiles above minimum spouting are found to follow a similarity relationship and an explicit equation for the circulation rate is developed using that relationship and the calculated voidage at the top of the spout. Criteria for stability and spouting regime identification are discussed.     

倾斜压差移动床中的气固流动

应用散体力学及多相流理论,分析倾斜压差移动床中的气固流动,推导出倾斜压差移动床的力平衡方程和空隙率方程,从而使计算固定床压降及气体流率的Ergun方程、Lewis方程及Kwank方程,可以普遍地适用于垂直和倾斜的移动床压降及气体流率的计算。 选用三种颗料状物料,在四种不同倾斜度的斜管中测定了不同负压差和固体流率条件下的气体流率。计算结果与大量实验数据吻合。     

安塞特低渗透长6储层整体暂堵重复压裂技术

安塞油田采用注采同步开发,在注水开发过程中,由于部分区块微裂缝发育或地层堵塞,存在地层压力上升,老井低液面、低流压、采液和采油指数下降,常规重复压裂效果不理想。为提高单井产量,保持油田长期稳产,通过多年的不断试验与探索、发展与完善、总结与认识,工艺逐步突破,研究出了适合安塞油田地质特征的裂缝暂堵复压工艺及选井选层标准,取得了较好的经济效益,为特低渗透油田高效开发提供了技术对策。     

Pressure gradients,voidage and gas flow in the annulus of spouted beds

Parallel measurements of pressure gradients with a differential pressure probe and voidage profiles with a fibre optic system have been carried out to study gas flow distributions in the annulus of spouted beds. The observation of Grbavcic et al. (1976) that for a given fluid‐solid combination and column geometry the annulus pressure gradient at any bed level is independent of bed depth was corroborated again. Calibration curves of pressure drops versus superficial gas velocities for beds of voidage higher than the loose‐packed voidage were obtained by applying the Ergun (1952) equation, making it possible to estimate superficial gas velocities in the annulus using the static pressure gradient method. The local superficial gas velocity in the annulus was found to be higher in a deep bed than in a shallow bed of the same material, contrary to the conclusion (Grbavcic et al., 1976) that, for a given fluid‐solid combination and column geometry, the annulus fluid velocity at any level is independent of bed depth. Theoretical models and equations which do not account for the conical geometry near the bottom were found to underpredict superficial gas velocities in the annulus. Increasing the spouting gas flow was found to increase the net gas flow through the annulus.     

MODELLING GAS-SOLID FLOW IN A PNEUMATIC-FLASH DRYER

Investigations of aerodynamics of gas-solid flow in a pneumatic-flash dryer in semiindustrial scale have been carried out. Apparatus was composed of three elements with varying cross-sectional area connected together, i.e. expanding cone, decreasing cone and a vertical pipe with constant diameter. A mathematical model of the dryer is based on the continuity equations for both gas and solid phase and on differential equations for momentum balance of the gas-solid mixture and momentum balance of the solid phase. The model has been solved by means of Gear's numerical method. The effect of various empirical correlations for the solid-wall friction factor has been shown. Distributions, resulting from the model, for pressure, gas velocity, panicle velocity, voidage and residence time of panicle along the axis of apparatus have been presented. The results of numerical calculations have been verified on the basis of measurements in pan.     

Characteristics of fluidisation behaviour in a pressurised bubbling fluidised bed

The experiments were carried out in a bench‐scale fluidised bed of 90 mm in diameter to determine the influence of pressure on fluidisation characteristics of Geldart A and B particles over the range of pressure 0.1–4.5 MPa. For Geldart B particles, the results indicate that minimum fluidisation velocity (u_mf) was found to decrease with pressure whilst bed voidage at u_mf was unaffected, and the bed expansion height increase with pressure at fixed value of gas velocity was observed for both Geldart B and A particles. For Geldart A particles, minimum bubbling velocity (u_mb) bed voidage at u_mb and dense phase voidage were found to increase obviously with pressure, but a slight influence of pressure on u_mf was observed. The prediction values of high‐pressure fluidisation characteristics from the references' correlations developed at pressure were in agreement with the experimental data. © 2012 Canadian Society for Chemical Engineering